How to Clean Green Pool Water: A Comprehensive Guide
Green pool water signals a bloom of algae, microscopic plants thriving on sunlight, warmth, and nutrients. Cleaning it requires a multi-step process involving testing water chemistry, shocking the pool with chlorine, scrubbing the surfaces, and filtering the water to remove the algae and its byproducts.
Identifying the Culprit: Why Is Your Pool Green?
Before diving into the cleaning process, understanding why your pool turned green is crucial for preventing future blooms. Several factors contribute to algae growth:
- Inadequate Sanitization: Insufficient chlorine levels are the primary cause. Chlorine acts as a disinfectant, killing algae and preventing its growth.
- Poor Circulation: Stagnant water provides an ideal environment for algae to flourish. Pool pumps and filtration systems need to operate effectively.
- Imbalanced Water Chemistry: Incorrect pH, alkalinity, or calcium hardness levels can hinder chlorine’s effectiveness and promote algae growth.
- Excess Nutrients: Phosphates and nitrates, introduced by decaying leaves, lawn fertilizer runoff, and swimmer waste, provide food for algae.
- Sunlight: Algae, like all plants, needs sunlight to grow. While you can’t eliminate sunlight, you can manage other contributing factors.
The Step-by-Step Guide to Crystal Clear Water
Cleaning a green pool involves restoring proper water chemistry, eliminating the algae, and removing its remnants. Here’s a detailed breakdown:
1. Test and Balance Your Water
The first step is a comprehensive water test using a reliable test kit or taking a sample to a pool supply store for professional analysis. You need to know your:
- pH: Aim for a range of 7.2-7.8.
- Alkalinity: Aim for a range of 80-120 ppm.
- Calcium Hardness: Aim for a range of 200-400 ppm.
- Chlorine: A reading of 1-3 ppm is ideal for regular maintenance, but significantly higher levels are needed for shocking.
- Cyanuric Acid (Stabilizer): This protects chlorine from sunlight degradation. Keep it within the recommended range (30-50 ppm).
Adjust the pH and alkalinity before shocking the pool. Use appropriate chemicals, following the manufacturer’s instructions carefully. Add chemicals incrementally, retesting after each adjustment.
2. Brush the Pool Thoroughly
Scrub the pool walls, floor, and any other surfaces with a stiff-bristled brush. This dislodges the algae and allows the chlorine to penetrate and kill it more effectively. Pay particular attention to corners, crevices, and areas with poor circulation.
3. Shock the Pool with Chlorine
Shocking the pool involves adding a large dose of chlorine to kill the algae. The amount of shock required depends on the severity of the algae bloom.
- Light Green: Use a double dose of shock (e.g., 2 pounds of chlorine shock per 10,000 gallons of water).
- Medium Green: Use a triple dose of shock.
- Dark Green/Black: Use a quadruple dose of shock.
Always add shock at dusk or night, as sunlight degrades chlorine. Follow the manufacturer’s instructions precisely and wear protective gear (gloves and eye protection). Never mix different pool chemicals together.
4. Run the Filter Continuously
Run your pool filter 24/7 until the water clears. This will remove the dead algae and debris. Clean the filter regularly, backwashing (for sand filters) or rinsing the cartridge (for cartridge filters) as needed. A Diatomaceous Earth (DE) filter is particularly effective at removing fine particles.
5. Use Algaecide (Optional)
While not always necessary, an algaecide can help speed up the cleaning process and prevent future algae blooms. Choose an algaecide compatible with your pool type and follow the manufacturer’s instructions. Copper-based algaecides can stain light-colored pool surfaces if used improperly, so consider a polymeric algaecide as a safer alternative.
6. Vacuum the Pool
Once the water starts to clear, vacuum the pool to remove any remaining debris that settled on the bottom. If you have a severe algae bloom, you may need to vacuum to waste to avoid clogging your filter.
7. Re-test and Adjust Water Chemistry
After the water is clear, re-test the water chemistry and adjust as needed to ensure proper balance. Pay particular attention to chlorine levels and pH.
8. Preventative Maintenance
Once your pool is clear, consistent maintenance is key to preventing future algae blooms. This includes:
- Regularly testing and balancing water chemistry.
- Maintaining proper chlorine levels.
- Running the filter for an adequate amount of time each day.
- Brushing the pool regularly.
- Shocking the pool periodically (e.g., weekly or after heavy use).
- Using a phosphate remover to reduce nutrient levels.
- Ensuring proper circulation by keeping skimmer baskets clean.
Frequently Asked Questions (FAQs)
1. How long does it take to clear a green pool?
The time it takes to clear a green pool depends on the severity of the algae bloom and the efficiency of your cleaning process. It can range from a few days to a week or longer. Persistent dedication is vital.
2. Can I swim in a green pool?
No. Swimming in a green pool is not recommended. Algae can harbor bacteria and other harmful microorganisms, posing a health risk. Moreover, the high chemical levels used to treat the algae can irritate skin and eyes.
3. What type of chlorine should I use to shock my pool?
Calcium hypochlorite (cal hypo) is a common and effective type of chlorine for shocking pools. However, liquid chlorine (sodium hypochlorite) and dichlor (dichloroisocyanurate) are also options. Carefully consider the pros and cons of each, including their effect on pH and cyanuric acid levels.
4. How often should I shock my pool?
You should shock your pool weekly or after heavy use, such as after a pool party or after a heavy rainstorm. Shocking helps maintain proper sanitation and prevent algae blooms.
5. What is black algae and how do I get rid of it?
Black algae is a particularly stubborn type of algae that appears as dark spots or stains on pool surfaces. It has a protective outer layer that makes it resistant to chlorine. To get rid of it, brush the affected areas vigorously with a stainless steel brush, shock the pool with a higher dose of chlorine, and use an algaecide specifically designed for black algae.
6. Can I use baking soda to raise the alkalinity in my pool?
Yes, baking soda (sodium bicarbonate) can be used to raise the alkalinity in your pool. Add it gradually, following the instructions on the packaging, and retest the water chemistry after each addition.
7. What are phosphates and why are they bad for my pool?
Phosphates are nutrients that algae feed on. They can enter the pool through decaying leaves, lawn fertilizer runoff, and swimmer waste. High phosphate levels can promote algae growth, even when chlorine levels are adequate.
8. How can I remove phosphates from my pool water?
Use a phosphate remover. These products bind to phosphates, making them easier to filter out of the water. Regularly cleaning the pool and removing debris can also help reduce phosphate levels.
9. What is cyanuric acid (stabilizer) and why is it important?
Cyanuric acid (CYA), also known as stabilizer or conditioner, protects chlorine from degradation by sunlight. Without CYA, chlorine will quickly dissipate in the sun, making it ineffective at killing algae and bacteria.
10. My pool is clear, but still has a slight green tint. What should I do?
A slight green tint after shocking can indicate the presence of dead algae particles still suspended in the water. Continue running the filter until the water clears completely. Adding a clarifier can help these particles clump together, making them easier to filter out.
11. I have a salt water pool. Can algae still grow in it?
Yes, algae can still grow in salt water pools. Although salt water chlorinators generate chlorine, it is still important to maintain proper water chemistry and sanitation to prevent algae growth. The chlorine level should be checked regularly.
12. What if I’ve tried everything and my pool is still green?
If you’ve tried all the steps and your pool is still stubbornly green, it’s time to consult a professional pool service company. They have the expertise and equipment to diagnose and resolve complex pool water chemistry issues. They may uncover underlying problems with the filtration system or other equipment that are contributing to the algae growth.